I also have a little python script that does this including working out pension contributions and health insurance BIK. You need to update the 1st, 2nd, 5th and 6th rows with whatever your respective values are.
Find it much easier to use things like this because I can get an instant check on what it'll cost to change my pension contribution for example. The only thing it doesn't account for is pension contributions over 115k or your max % per age bracket, because I don't earn over 115k.
salary = 50000
bik = 0 credits = 3400 threshold = 36800 pension = salary * 0.0 employer_pension = 0.0
def lowTax(salary, pension, threshold, bik): if (salary + bik) > threshold: return threshold * 0.2 else: return (salary + bik) * 0.2
def highTax(salary, pension, threshold, bik): if (salary + bik) > threshold: return ((salary - pension + bik) - threshold) * 0.4 else: return 0
def prsi(salary, bik): return (salary + bik) * 0.04
def usc(salary, bik, lowSal, midSal, highSal, lowRate, midRate, highRate, veryHighRate): salary = salary + bik if salary <= lowSal: return salary * lowRate if salary > lowSal and salary <= midSal: return (lowSal * lowRate) + ((salary - lowSal) * midRate) if salary > midSal and salary <= highSal: return (lowSal * lowRate) + ((midSal - lowSal) * midRate) + ((salary- midSal) * highRate) if salary > highSal: return (lowSal * lowRate) + ((midSal - lowSal) * midRate) + ((highSal - midSal) * highRate) + ((salary - highSal) * veryHighRate)
totTax = lowTax(salary, pension, threshold, bik) + highTax(salary, pension, threshold, bik) - credits prsi = prsi(salary, bik) usc = usc(salary, bik, 12012, 21295, 70044, 0.005, 0.02, 0.045, 0.08) totLiability = totTax + usc + prsi pension_tot = (pension / 12) + (salary / 12 * employer_pension) print('Total liability: ', totLiability) print('Annual salary after tax: ', salary - pension - totLiability) print('Monthly salary after tax: ', (salary - pension - totLiability) / 12) print('Monthly pension contribution: ', pension_tot)